In high pressure fluid pumps having reciprocating plungers, it is necessary to provide a seal around the plunger to prevent the leakage of high pressure fluid. In such pumps, the seal must be able to operate in a high pressure environment, withstanding pressures in excess of 10,000 psi, and even up to and beyond 50,000-70,000 psi.
Currently available seal designs for use in such an environment include an extrusion resistant seal supported by a back-up ring, the back-up ring and seal being held by a seal carrier. However, the tolerances for clearance between the plunger and back-up ring are very difficult to achieve and maintain. Very typically, therefore, the plunger and back-up ring come into contact, generating frictional heating, which in turn causes the seal to fail.
Accordingly, there is a need in the art for an improved high pressure fluid seal assembly, and in particular, a seal assembly that is simple to manufacture accurately, and that will increase the life of the seal. The present invention fulfills these needs, and provides further related advantages.